Re: [hylafax-users] MODEM Command Error

Thanks for explaining most of this stuff to me. I also found those
hylafax pages the go knee deep on how the modem works.

This problem where we have to depend on the other modem to sync-up to
me is an issue. Is there a way for me to test this bug against my USR
modem? I have a fax machine but it never fails when I fax it to
hylafax. Do you know a set of modem command that would simulate
sending a fax and will repetadely show the failure of the AT+FRH=3 and
AT+FTRS=7 ?

Thanks for all your help

On 5/8/07, Lee Howard <faxguy@xxxxxxxxxxxxxxxx> wrote:

The AT+FRS=n command is an extremely useful command which allows the
Class 1 driver to "sync up" nearly on-demand, anytime it's used. There
really is no substitute for it, either. Sometimes one can use AT+FRH=3
and, without getting a CONNECT, we can wait for a NO CARRIER ... but
that's not consistent over modems, either, and it's really (in my
opinion) a mis-use of the +FRH=3 command. The entire purpose of
AT+FRS=n is to allow proper synchronization... and resynchronization.

The log you've provided below is a perfect example of why the +FRS=n
command is so important. Without it, we depend on the other end to have
the ability to sync-up with us (instead of us syncing up with them). If
neither of us can sync up with the other then if we lose the initial
synchronization (or never establish it in the first place) then what you
see in the logs will happen.

USR modems, like yours, using the TI/USR/3Com chipset (some recent
"winmodem" USRs use Conexant chipsets) seem to have problems sometimes
after using +FRS=n. This is unfortunate. There are also many other
modems that don't support +FRS=n at all.

You're welcome to try Class 2.0 and see if you fare any better, but you
probably will have a different set of problems there.

If you have Caller*ID support then you could switch on-the-fly between
Class 2.0 and Class 1 depending on the caller... but getting that all
tuned right seems like a lot of work compared, maybe, to just buying a
different modem.

--
"Nothing is impossible for the person that doesn't have to do it"
"The probability of anything happening is in inverse ratio to its desirability"
"If I were a roman statue, I'd be made alabastard"
--
George H
george.dma@xxxxxxxxx